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应用~(15)N同位素标记和Tn5转座子诱变技术研究了固氮粪产碱菌对宿主水稻根表的联合进程。结果表明,固氮菌在根表的结合分三个不同的步骤,即粘附、定位和定殖。接种3h后粘附在根表的菌体数量达最大值,约占接种量的3.7％。粘附的菌体易脱离根表,表明粘附作用是细菌与宿主植物间弱的相互作用。接种15h后,定位菌体数量达最大值,约占接种量的21％。经振荡处理不能使定位菌体脱离根表。接种20h后定殖菌体紧密结合于根表,剧烈振荡亦不能使其脱离根表。定殖后菌体开始表现出果胶酶活性。趋化缺陷型(che~-)菌株仅丧失部分粘附能力,并保持在根表的定位能力。胞外多糖丰富型(exo~(++))和胞外多糖缺陷型(exo~-)菌株均部分丧失了定位能力。趋化和胞外多糖同时缺陷型(che~-exo~-)菌株在根表的粘附和定位能力低于野生型菌株。粪产碱菌在水稻幼苗根表没有专一的粘附部位,但粪产碱菌的定位和定殖主要发生在主根根表,尤其是主、侧根交接处。
The combined process of host-rice root surface with the use of ~ (15) N isotope labeling and Tn5 transposon mutagenesis was studied. The results showed that the combination of azotobacter in the root table divided into three different steps, namely, adhesion, localization and colonization. 3h after inoculation in the root of the number of cells reached the maximum amount of about 3.7% of the inoculum. The adherent bacteria are easily detached from the root surface, indicating that the adhesion is a weak interaction between the bacteria and the host plant. After inoculation 15h, the maximum number of locating cells, accounting for about 21% of inoculation. Oscillation treatment can not make the positioning of bacteria from the root table. Inoculated with bacteria 20h after inoculation with the root table, violent oscillation can not make it from the root table. After colonization began to show pectinase activity. Chemotaxis-deficient (che ~ -) strains only lost part of their ability to adhere and maintained their ability to localize in the root. Extracellular polysaccharide-rich (exo ~ (++)) and exo-deficient (exo ~ -) strains were partially lost the ability to locate. Chemotaxis and exo-polysaccharide co-deficient (che ~ -exo ~ -) strains in the root surface adhesion and localization ability than wild-type strains. Alcaligenes faecalis did not have a specific adhesion site in the root of rice seedlings, but the colonization and colonization of Alcaligenes faecalis occurred mainly in the root of the main root, especially the lateral and lateral roots.